<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>demo-item-same-height2.html</title>
    <style>
      * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
      }
      body {
        height: 100vh;
        width: 100vw;
        display: flex;
        flex-direction: column;
      }
      header {
        height: 80px;
        background: #eee;
      }
      footer {
        height: 40px;
        background: #eee;
      }
      main {
        flex: 1;
        display: flex;
      }
      main aside {
        width: 200px;
        border: 1px solid #000;
      }
      main section {
        flex: 1;
      }
    </style>
  </head>
  <body>
    <header></header>
    <main>
      <aside></aside>
      <section></section>
    </main>
    <footer></footer>
  </body>
</html>
